package chapter8;

/**
 * Created by lenovo on 2016/3/29.
 */
public class StackTranceDemo {
    public static void main(String[] args) {
        try{
            c();
        }catch(NullPointerException ex){
            ex.printStackTrace();
        }
    }

    static void c(){
        b();
    }

    static  void b(){
        a();
    }

    static String a(){
        String text=null;
        return text.toUpperCase();
    }
}
